A light fixture may include an LED and an LEP (which is also generally referred to as a waveguide) that are positioned within a light fixture structure such as a metal (e.g., aluminum) frame, housing or cover. The LEP may illuminate a space around the LEP based on lumen transfer from the LED to the LEP. The LEP may receive light from the LED through an edge of the LEP and emit out the light through a broad side of the LEP. To achieve a desired lumen transfer from the LED to the LEP, the LED and the LEP need to be maintained within a certain distance from each other. Because a gap between the LED and the LEP may change in response to changes in temperature of the LEP, the initial gap size needs to be selected based on a particular temperature range the LEP may experience. For example, a gap of about 0.015 inches between the LED and the LEP may enable approximately 93% lumen transfer from the LED to the LEP. However, the gap between the LED and the LEP may increase if the LEP shrinks away from the LED at lower temperatures, resulting in a less efficient lumen transfer between the LED and the LEP.
While a large gap between the LED and the LEP may result in inefficient lumen transfer from the LED to the LEP, a small gap may cause the LEP to bend due to lack of lateral space for thermal expansion. For example, as the temperature of the LEP increases, the LEP may expand and come in contact with the LED, possibly causing a failure of the LED if the LEP continues to expand. Once the LEP comes in contact with the LED, further thermal expansion of the LEP may also result in bending or fracturing of the LEP. An LEP that is bent may distort light and result in uneven distribution of light emanating from the LEP. Further, frequent bending of the LEP may cause mechanical stress of the LEP, resulting in cracking and/or deformation of the LEP. In addition, to allow the LEP to expand and shrink within the light fixture in response to temperature changes, the light fixture generally includes mechanical assemblies with springs or slotted screw holes.
Accordingly, a structure that will maintain or improve lumen transfer from the LED to the LEP without experiencing excessive mechanical stress is desirable.
The drawings illustrate only example embodiments and are therefore not to be considered limiting in scope. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or placements may be exaggerated to help visually convey such principles. In the drawings, reference numerals designate like or corresponding, but not necessarily identical, elements.